Azimuth reader for magnetic compasses



Feb. 9,1926. 1,572,528

C. G. GUY

AZIMUTH READER FOR MAGNETIC COMPASSES Filed March 25 1925 'micql Patented Feb. 9, 1926.

UNITED sTArEs PATENT UFFICE.

CHARLES G. GUY, OF VANCOUVER, BRITISH COLUMBIA, CANADA.

AZIMUTH READER FOR MAGNETIC COMPASSES.

Application filed. March 25, 1925. Serial No, 18,320. i

To aZZ whom it may concern:

, Be it known that I, CHARLES G. GUY, a citizen of the Dominion of Canada, residing at Vancouver, in the Province of British Columbia, Canada, have invented certain new and useful Improvements in Readers forMagnetic Compasses, of which the following is a specification.

This invention relates to a magnifying reader and azimuth sight for a marine compass and has been designed as a simple removable attachment to the dial glass of any compass, compass corrector or pelorus.

While numerous devices are at present used to serve these several purposes, all with which I am acquainted are relatively expensive to manufacture and are not applicable to a compass of small size.

The device, which is the subject of this application, is extremely simple in construction, can be readily applied without alteration to the glass of even the smaller sizes of marine compasses and combine a lens for magnifying the reading, which lens is revolvable in its supports and is provided with a sighting vane and light shades so that a bearing may be taken of any object, whether terrestrial or celestial.

The device may also be removed from the compass and applied to the azimuth card or plate of a compass corrector or pelorus.

The invention is fully described in the following specification, reference being made to the drawings by which it is accompanied, in which:

Fig. l is a front elevation.

Fig. 2, a sectional elevation on the line 2-2 in Fig. l, and

Fig. 3, a plan.

The device comprises a planoconvex lens 2, the frame 8 of which has trunnions at by which the lens and its frame are mounted in a supporting frame 5, 6.

This supporting frame consists of uprights 5 connected by a bottom rail or bar 6. The lower ends of the uprights 5 are laterally enlarged, as shown in Fig. 2, to afford a sufiicient footing for the frame on the glass 20 of the compass. The cross rail 6 is curved upward from its connection to the feet of the uprights 5 to allow for the introduction beneath it of a circular suction disc 7 of rubber or the like to the centre of which disc is secured a screw 8 which passes through an aperture in the middle of e rail 6 and is provided above the rail wi Azimuth milled nut 9 by which the frame 5 6 may be held securely to the glass by the suction of the disc 7. I

On one of trunnions 4t is'a milled nut 10 by whichthe lens maybe clamped be tween the uprights 5 at any desired angle and by which, when the clamp is released. the lens may be rotated on its trunnions.

A sight vane 11 having the customary medial slit is pivotally mounted to the lens frame 3 at a position exactly ninety degrees from the axis of the trunnions 4, which sight vane is curved to fold down along'the outer side of the lens frame 3. Diametrically opposite the sight vane of the lens frame has a V-notch 13 with which. the

pointed end of thesight vane maybe aligned The device is applied to a compass by removing or slackening back the nut 9 on the screw 8 that the suction disc may be pressed tightly on the glass to exclude the air. Thereafter the nut 9 is lightly applied to hold the frame 5 6 on the glass, care being taken to centre the device with the card.

In taking a bearing of a terrestrial object, which is presumably of only slightaltitude, the frame 5 6 in which the lens is mounted, is turned on its screw 8 until the alignment of the sight vane 11 and notch 13- bear on the object. The lens being approximately horizontal, the compass hearing may be easily read off the card.

In taking a celestial bearing, the sighting vane 11 and notch 13 are approximately aligned on the object and the lens 2 is turned on its trunnions to a sufficient angle to get a reflection of the object down on to the edge of the compass card, one or the other of the shades 14: being turned up for use as necessary. 7

In using the device with a compass corrector or pelorus, the suction disc 7 is removed from the glass of the compass and transferred to the card of the compass corrector.

From the foregoing description it will be seen that the device is simple to manufacture and in the simple and efiective means by which it is attached to the glass of a compass enables it to be quickly applied to a compass of any size within the width of the supports 5 apart.' And yet with this simplicity it readily serves the purpose of three separate instruments in common use.

Having now particularly described my invention, I hereby declare that what I claim as new and desire to be protected in by Letters Patent, is:

g 1. An azimuth reader of the class described, comprising in combination, a lens, a trunnioned frame in which the lens is secured, said frame having a sighting vane and V notch at right angles to the axis of the trunnions, a frame in whichthe trunnions of the lens frame are mounted, and means for at taching the supporting frame by suction to a plane surface.

2. An azimuth reader, comprising in combination, a lens, a trunnion frame in which the lens is secured, said lens frame having a sighting vane and V notch at right angles to the axis of the trunnions, which sight ing vane'is pivoted, to the frame to fold alongsideit, a supporting frame in which the trunnions of the lens frame are mounted,

and means for attaching the supporting frame by suction to a'plane surface.

3. An azimuth reader of the class described, comprising in combination, a lens, a trunnioned frame inwhich the lens is secured, said frame havinga sighting vane and V notch at right angles to the axis of the trunnions, a light shade pivoted on the lens frame at the position of the notch, in frame in which the trunnions of the lenS frame are mountechand means for attaching the supporting frame by suction to a plane surface. i

4. An azimuth reader of the class described, comprising in combination, a lens,

a trunnioned frame in which the lens is secured, said frame having a sighting vane and V notch at right angles to the axis of the trunnions of the lens frame, a supporting frame in which the trunnions of the lens frame are mounted, said frame comprising uprights connected together by a cross bar, a rubber suction disc having athreaded stem secured to upwardly project from its centre, which stem passes upward through an aperture in the middle of the cross bar and a milled nut on'said stem above the bar.

In testimony whereof I affix my signature.

CHARLES G. GUY. 

